IRP study suggests COVID-19 prevalence far exceeded early pandemic cases

Tuesday, June 22, 2021

Researchers estimate nearly 17 million undiagnosed cases in the U.S. by mid-July 2020

In a new study, National Institutes of Health researchers report that the prevalence of COVID-19 in the United States during spring and summer of 2020 far exceeded the known number of cases and that infection affected the country unevenly. For every diagnosed COVID-19 case in this time frame, the researchers estimate that there were 4.8 undiagnosed cases, representing an additional 16.8 million cases by July alone. The team’s analysis of blood samples from people who did not have a previously diagnosed SARS-CoV-2 infection, along with socioeconomic, health, and demographic data, offers insight into the undetected spread of the virus and subgroup vulnerability to undiagnosed infection.

“This study helps account for how quickly the virus spread to all corners of the country and the globe,” said Bruce Tromberg, Ph.D., director of the National Institute of Biomedical Imaging and Bioengineering (NIBIB), one of the NIH institutes who run the NIH SARS-CoV-2 Seroprevalence Project. “The information will be invaluable as we assess the best public health measures needed to keep people safe, as new — and even more transmissible — variants emerge and vaccine antibody response changes over time.”

In addition to NIBIB, the research team includes scientists from the National Institute of Allergy and Infectious Diseases (NIAID), the National Center for Advancing Translational Sciences (NCATS); and the Frederick National Laboratory for Cancer Research, sponsored by the National Cancer Institute (NCI). Their report in the June 22, 2021, early online issue of Science Translational Medicine represents the first data from the 12-month NIH study that was launched in April 2020.

Colorized scanning electron micrograph of an apoptotic cell (blue) infected with SARS-COV-2 virus particles (orange), isolated from a patient sample.